When a magnetic disk, i.e. a hard disk drive medium disk is assembled to the spindle motor, the disk clamp should provide sufficient clamping force to tighten the magnetic disk and eliminate relative movement of the magnetic disk to the motor hub.
In conventional hard disks, an external bolt is used to secure the disk clamp to the spindle motor. As a result, it is difficult to reduce the height of the hard disk drive. Further, the deflection of the magnetic disk is too great for magnetic disks of high areal densities.